1. Field of the Invention
The present invention relates to a semiconductor device, and more particularly to, a semiconductor device having a structure capable of suppressing oxygen diffusion and a method of manufacturing the same.
2. Description of Related Art
A semiconductor device technology, including a MOSFET (metal oxide semiconductor field effect transistor) having excellent on/off characteristics of an electronic device, has been rapidly developed through miniaturization and integration on the basis of silicon since 1960's, becomes a core technology of current mobile computing and communication devices and is widely applied to a variety of fields.
A method of manufacturing a device including the MOSFET is described with reference to FIG. 1. The method comprises processes of forming a MOSFET device part having a gate consisting of a gate dielectric film 2 and a gate electrode 3, a source and a drain on a semiconductor substrate 1, depositing an interlayer insulation film 4, forming contact holes 5 penetrating therethrough, filling the contact holes 5 with a conductive material 6 and forming a metal wiring 7. The device including the MOSFET has merits that the on/off characteristics are more sensitive than the other devices and miniaturization and integration thereof can be made by making the gate electrode small, making the gate dielectric film thin and increasing a dielectric constant while minimizing a change in process facilities.
In order to enable the MOSFET to smoothly operate, it is important to adjust electrical properties by adjusting characteristics of the respective thin film materials. For example, a research for changing materials of the MOS structure of which a substrate, a channel, a dielectric film and a gate electrode material are Si, SiO2 and/or poly-Si into a high-mobility channel such as Ge or group compound semiconductor, a dielectric film having a high dielectric constant (high-k) such as HfO2 and a metal gate electrode having no depletion of charges has been actively carried out. For the metal wiring, in order to further reduce the dielectric constant of the interlayer dielectric film 4 and to thus reduce an RC delay, a method of introducing a material such as SiOC to manufacture a device has been studied and developed.
In the meantime, the semiconductor device manufacturing method includes several tens to hundreds of processes. In order to increase a yield of the device manufacturing process, it is important to maintain and secure the characteristics of the materials, which are used for the MOSFET device manufacturing process, even when the materials are subject to a thermal process, in which the diffusion speed between the materials increases, and an oxygen introduction process, particularly, for example. In particular, the diffusion speed of the oxygen is fast and most of oxidation reactions are thermodynamically stable, so that the oxygen causes an unwanted oxidation process of the material used for the semiconductor process, which again causes physical and chemical reactions such as a volume expansion and a change in composition. A wet cleaning process of the related art, which is performed so as to clean a surface before the deposition or after the etching, is focused to remove the surface contaminants. That is, there is no effect such as diffusion suppression through surface modification. When impurities increase in the gate dielectric film or a composition thereof is changed even slightly, an electrical trap is formed to deteriorate the electrical characteristics of the gate dielectric film. In a case of the high-k dielectric film, when the oxygen diffusion occurs, a non-uniform oxide film grows between a channel layer of the substrate 1 and the gate dielectric film 2, so that the dielectric constant may be decreased. Also, when the oxygen diffusion occurs in a direction facing towards the gate electrode 3 from the gate dielectric film 2, a leakage current of the gate dielectric film may be increased. Also, the oxygen diffusion into the interlayer insulation film 4 may cause an increase in the dielectric constant, thereby reducing the device operating speed.
The information disclosed in the Background of the Invention section is provided only for enhancement of (or better) understanding of the background of the invention, and should not be taken as an acknowledgment or any form of suggestion that this information forms a prior art that would already be known to a person skilled in the art.